1. Field of the Invention
The present invention relates generally to shear-resistant apparatus for joining planar woven materials such as fabric used in shoe closures. The present invention relates specifically to means and apparatus for joining two pieces of fabric wherein one piece of fabric is provided with a filamentary hook gripping surface for releasable coupling with a woven surface of the second piece of fabric.
2. Prior Art
The technology underlying design of shoe soles and uppers has progressed significantly in the recent past, but little progress has been made in designing suitable closures for shoes which prevent accidental opening of the closure, thereby allowing the foot to slip out of the shoe. Since the invention of shoelaces and buckle clasps for shoes, few other methods of closure have been attempted. The invention of material sold under the trademark Velcro, a two-part securement means comprising a first surface provided with plural filamentary hooks and a second surface provided with plural filamentary loops which engage the hooks, has permitted further advancement in the technology of shoe closures
Development of most prior shoe closures has focused on the structure of the closure straps rather than the placement of the Velcro strips or other fastening means. For example, U.S. Pat. No. 4,275,513 (Antonious) discloses a shoe having separable fastening members co-acting with flexible gripping elements such as hook and loop Velcro-type fasteners. The location and structure of the separable fastening members enables a person having only one arm, or an artificial limb, to secure the closure with one hand.
Similarly, U.S. Pat. No. 4,282,657 (Antonious) discloses a heel restraint secured by an adjustable, flexible closure assembly using two-part hook and loop Velcro fastening surfaces. Prior to these inventions, an adjustable and flexible shoe closure was developed, enabling the wearer to pull the uppers of the shoe inwardly and fasten the shoe using only one hand. Such a closure preferably uses two-part Velcro-type fasteners, as disclosed in U.S. Pat. No. 4,270,285 (Antonious).
The foregoing references demonstrate the use of two-part Velcro with strap-type fasteners for shoes. However, such fasteners have significant aesthetic and functional drawbacks which limit their application. For example, some shoe designers consider that the strap-type fasteners used in the Antonious references have a "clunky" appearance which is undesirable from an aesthetic point of view.
An attempt has been made to combine the attractive aesthetic features of traditional shoelaces with a slip-resistant binding, as disclosed in U.S. Pat. No. 4,247,967. The Swinton disclosure relates to providing a shoelace with hook and loop Velcro surfaces so that a hook surface provided on one end of the shoe lace mates with a loop surface provided on a second end of the shoe lace. Thus, when the shoe lace is tied in a traditional bow knot, at least one portion of each Velcro loop gripping surface will co-act with a portion of an oppositely configured Velcro hook surface. This results in a shoelace knot having high shear strength and resistance to slippage.
Unfortunately, Swinton requires providing a shoelace with both a hook and a loop Velcro surface, a process which is difficult to manufacture and requires a significant amount of materials and additional manufacturing efforts, since different types of Velcro material must be secured to the shoelace.
In contrast, the present invention takes advantage of the natural filamentary loop properties of a typical woven fabric shoelace. Specifically, the present invention recognizes that a hook-type Velcro surface will easily mate with a variety of woven fabrics, since such fabric inherently includes a plurality of tightly connected thread loops which form the fabric. Thus, when the filamentary hooks of a first Velcro surface are brought into contact with a woven fabric shoelace, the hooks will engage the thread loops of the woven fabric, thereby coupling the pieces together.
Such an arrangement manifests the same high resistance to shear stress exhibited by traditional two-part Velcro having a hook surface and a loop surface. However, the inventive arrangement does not require purchasing the loop segment of Velcro and separately securing it to the shoelace or other fabric. Thus, the inventive apparatus costs significantly less than competing methods and requires fewer materials and manufacturing costs. The present invention also does not require alignment between Velcro hook and loop surfaces, since the filamentary hooks of the present invention will couple with loops in the fabric regardless of the location on the fabric touched by the hooks.
Thus, the prior art appears deficient in not providing means for joining two fabric segments in an arrangement having high resistance to shear stress, while permitting easy separation of the fabric elements when desired.